Conventional LCDs operate by projecting light through a layer of liquid crystals and applying varying amounts of electrical charge to the liquid crystals in order to change the color and intensity of the display. Typically, the layer of liquid crystals is contained within a small gap formed between a color filter glass and a thin film transistor (TFT) glass.
Some mobile devices, such as mobile phones, touchpads, portable computers, portable media players, and the like, include a metal ring built around the edge of the TFT glass of the LCD. The metal ring can be coupled to the system ground of the device to provide isolation between the LCD and the device's antenna, thereby reducing the amount of noise in the antenna that is caused by the LCD. Generally, larger metal rings provide better isolation between the LCD and antenna.
While a TFT glass coated with a thick layer of metal is desirable for reducing the amount of noise experienced by the device's antenna, the metal ring adds to the length and width of the TFT glass, and, thus, adds to the length and width of the device. As consumers seek more compact mobile devices, the bulk added by the metal ring can be undesirable.